Freshwater Mussel Survey of Clinchport, Clinch River, Virginia ......depth was approximately 20 cm....
Transcript of Freshwater Mussel Survey of Clinchport, Clinch River, Virginia ......depth was approximately 20 cm....
Freshwater Mussel Survey of Clinchport, Clinch River, Virginia: Augmentation Monitoring Site: 2006
By:
Nathan L. Eckert, Joe J. Ferraro, Michael J. Pinder, and Brian T. Watson
Virginia Department of Game and Inland Fisheries Wildlife Diversity Division
October 28th, 2008
Table of Contents Introduction....................................................................................................................... 4 Objective ............................................................................................................................ 5 Study Area ......................................................................................................................... 6 Methods.............................................................................................................................. 6 Results .............................................................................................................................. 10
Semi-quantitative .................................................................................................. 10
Quantitative........................................................................................................... 11
Qualitative............................................................................................................. 12 Incidental............................................................................................................... 12
Discussion......................................................................................................................... 13 Acknowledgements ......................................................................................................... 17 Literature Cited .............................................................................................................. 18 Tables .............................................................................................................................. 19 Figures ............................................................................................................................. 25 Appendix I ....................................................................................................................... 39
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List of Tables Table 1 .............................................................................................................................. 19 Table 2 .............................................................................................................................. 20 Table 3 .............................................................................................................................. 21 Table 4 .............................................................................................................................. 22 Table 5 .............................................................................................................................. 23 Table 6 .............................................................................................................................. 24
List of Figures Figure 1 ............................................................................................................................. 25 Figure 2 ............................................................................................................................. 26 Figure 3 ............................................................................................................................. 27 Figure 4 ............................................................................................................................. 28 Figure 5 ............................................................................................................................. 29 Figure 6 ............................................................................................................................. 30 Figure 7 ............................................................................................................................. 31 Figure 8 ............................................................................................................................. 32 Figure 9 ............................................................................................................................. 33 Figure 10 ........................................................................................................................... 34 Figure 11 ........................................................................................................................... 35 Figure 12 ........................................................................................................................... 36 Figure 13 ........................................................................................................................... 37 Figure 14 ........................................................................................................................... 38
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Introduction
Freshwater mussel populations have experienced dramatic declines across the
country when comparing the current assemblages to historical accounts. Among the 297
species historically known from the U.S., nearly 70 % are presently classified as
threatened, endangered or extinct (Neves 1999). Similarly, of the 81 freshwater mussel
species recognized in Virginia, 37 (46%) are listed as threatened or endangered, with 32
occurring in the Clinch, Powell, and Holston river watersheds of Virginia’s upper
Tennessee River drainage.
Recent advancements in propagation techniques have led to widespread attempts
to restore declining or extirpated populations by releasing cultured juvenile mussels or by
translocating adult mussels. Many of these attempts have been made with little or no
scientific control with regards to determining success or failure. Before implementing
restoration activities, it is important to develop baseline information at the release point
that includes habitat suitability, mussel assemblage, mussel density, mussel age class
structure, host fish presence, and presence or absence of target species (Strayer and Smith
2003). All of these factors must be considered when determining the effectiveness of
long-term mussel restoration activities.
In 2002, the Virginia Department of Game and Inland Fisheries (DGIF)
developed a strategy to restore freshwater mussels at six reaches within the upper
Tennessee River drainage. These reaches include four on the Clinch River, and one site
each on the Powell and North Fork Holston rivers (Figure 1). The main restoration
technique, termed augmentation, was to release translocated adults or propagated
juveniles into reaches where valid species records exist after 1980. Within each
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augmentation reach, a site was selected to develop a baseline to gauge success of mussel
restoration activities.
In previous years, sample sites have included the Clinch River at Clinchport
(Clinch River Mile [CRM] 213.2), Scott Co., (2001); Slant (CRM 223.6), Scott Co.,
(2005, Eckert et. al 2008); and Cleveland Island (CRM 270.8), Russell Co., (2002).
During 2004, two sites; the State Route 833 Bridge crossing (Powell River Mile [PRM]
120.3) and Fletcher Ford (PRM 117.3), were sampled in the Powell River, Lee County,
Virginia (Eckert et. al 2007). The present study (2006) sampled the Clinch River at
Clinchport (CRM 213.2) in Scott Co.
This is the first DGIF mussel survey at a site that was previously sampled. Some
comparisons can be made between the 2001 and 2006 surveys. However, sampling
conditions in 2001 were less than ideal, leading the authors to discount the results. The
present study will be considered the baseline data against which future restoration efforts
will be measured.
Objective At Clinchport, Clinch River, specific objectives of this study were:
1. To map mussel distribution, richness, and relative abundance at available suitable habitat including the state endangered spiny riversnail (Io fluvialis).
2. To quantify sections of high density mussel aggregations at the site.
3. To identify ideal mussel habitat at the site for mussel augmentation.
4. Compare results of the present study to previous sampling events at
Clinchport.
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Study Area
The site known as Clinchport is found at the town of Clinchport immediately
downstream of the confluence of the Clinch River and Stock Creek in Scott Co., Virginia
and is located at CRM 213.2 (Figures 2 & 3). The site is approximately 1.0 km from the
intersection of US 23 and Virginia 65. A swinging bridge, built in 1932, (VDOT
structure #9017) crosses the Clinch River just downstream of the site. This site was
selected as a representative of Virginia Freshwater Mussel Restoration Plan reach 2
which is defined as Clinchport downstream to the mouth of Dry Valley Branch, a
distance of approximately six river miles. This area has been sampled several times
previously (Table 1). Records from these samples can be compared to the current study.
Methods
Several factors should be considered when selecting a survey design. They
include survey goals, target populations, available resources, site characteristics and
general knowledge of mussel populations (Strayer and Smith 2003). When conducting a
survey it is important to plan sampling techniques that will provide the most useful
information possible. To ensure that the current mussel assemblage was accurately
measured, multiple sampling techniques were employed. The use of multiple sampling
techniques increases confidence in the validity of observed results (Strayer and Smith
2003).
Initial site reconnaissance
Prior to the initiation of a large scale quantitative mussel sample an initial site
analysis is necessary. Early reconnaissance of a potential survey site includes snorkeling
prospective areas to search for suitable habitat and the presence of live mussels. During
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these early site visits factors such as site accessibility and ease of sampling are
considered. In addition, notes are taken about rare species collections in the event that
they are not collected during future sampling.
Semi-Quantitative
The semi-quantitative portion of this survey included a systematic sample of the
entire site length using 1-m2 quadrats. The site was marked every 20 m with stakes and
every 40 m with ropes. Ropes were marked every 5 m across the stream with flagging
tape to provide lanes and a visual guide while sampling (Figure 4).
Each 20 m section was divided into lanes 5 m wide. Lanes were selected based
on the average width of each section, starting with the center of the stream and moving 5
m left and right. One sampler was assigned to each lane, and the longitudinal position of
the sampler within the lane was determined randomly. Sampling each lane begins by
staggering the starting position of every other sampler, one starts at 1 m then the next at 3
m, while the third sampler begins at 1 m again. From the staggered starting point, a 1-m2
quadrat was sampled every 4 m for a total of five quadrats sampled per sampler within
each lane. By this design, 5 m2 are sampled in an area that measures 100 m2; a total of
5% of the overall habitat within each lane (Figure 5).
At every quadrat, depth, habitat type, visibility and dominant substrate class were
recorded. Mussels on the surface were collected and then the large substrate was
removed with the remaining substrate gently fanned to reveal additional mussels near the
surface. Every mussel was identified, counted and measured. In addition, presence of
the spiny riversnail was recorded.
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By beginning the survey with this method, it is possible to delineate the areas of
highest mussel density within the site. After determining the areas of highest density,
quantitative sampling was conducted to assess the density of mussels within the mussel
bed. Upon completion of the entire survey (semi-quantitative, quantitative, and
qualitative), the semi-quantitative data was statistically analyzed to verify the location
selection for quantitative sampling. Analysis of Variance was conducted (with multiple
comparisons, P < 0.05) to find significant differences between sections sampled. Any
significant difference indicates an area of higher mussel density which may be sampled
quantitatively. Data from the semi-quantitative sample was graphed using spatial
analysis in ArcMap 9.1 (ESRI) to visually highlight areas of higher density.
Quantitative
The area of highest mussel density during semi-quantitative sampling was
selected for quantitative sampling. Quantitative sampling was used to estimate
population size and age structure for monitoring purposes. The quantitative sampling
approach involves random sampling within the selected area using 0.25-m2 quadrats. A
small grid was constructed using an x,y coordinate system. Within the small grid, 100-
0.25-m2 quadrats were randomly selected. Each quadrat was excavated using a Ferraro
streambed sampler; these samplers are built with perforated aluminum, which allows
flow through the sampler, while maintaining enough rigidity to handle a large volume of
substrate (Figure 6). First, the mussels on the surface are removed, identified, counted,
and measured, and then the substrate was excavated into the sampler; typical excavation
depth was approximately 20 cm. Substrate from the quadrat was then placed in a set of
nested sieves (2.54 cm, 1.27 cm, 0.64 cm) and washed to reveal subsurface mussels. The
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purpose of sieving substrate was to collect and identify juvenile mussels which are
usually not collected in sampling without excavation; any mussel less than 30 mm was
considered a juvenile. All subsurface mussels were identified, counted, and measured,
and then the data were compiled to determine mean density and precision, target of which
was 25%. The Dunn equation for precision, a modified Downing and Downing equation,
[N = ((2*SD)/ (P*X)) 2] was used because it is easy to manipulate and can provide both
the precision of the mean and the number of samples needed to obtain the desired
precision level (Dunn 2000). Upon completion of quadrat sampling the final precision
was calculated.
Qualitative
Upon completion of the quantitative sampling, a qualitative sample was taken to
determine additional species not found using earlier sampling methods. A qualitative
sample is often more effective in detecting the presence of rare species than a quantitative
sample (Strayer and Smith 2003). The qualitative sample was conducted systematically
in 20 m sections in a similar fashion to the semi-quantitative sample. Samplers either
snorkeled or used a view bucket and kept record of live and relic mussels during a 20
minute sample of each section. Observations were recorded at the end of each 20 m
section and the total sample was compiled into an overall list of live and relic species
observed.
Incidental
During any intensive multi-layered quantitative survey there are ample
opportunities for samplers to encounter mussels outside of structured sampling. This
includes mussels observed during preliminary site surveys, site preparation and mussels
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that are found near but outside of sampling quadrats. Species found live in this manner
that are not otherwise collected in structured sampling will be recorded as incidental
finds.
Results
Semi-Quantitative
The semi-quantitative sample at Clinchport included 498-1-m2 quadrats. The
sample area was 171 m long, approximately 45 m wide at the island and 62 m wide above
for a total sample area of 10,173 m2 (Figure 7). Average depth of the site was 45.6 cm,
ranging from 0 cm to 91 cm (Figure 8). Visibility was generally greater than one meter.
Stream discharge was in decline from 440 CFS down to 366 CFS during the three days of
sampling (Greg Johnson, USGS, pers comm.). Substrate was predominantly gravel
(51%), and cobble (20%) with lower percentages of pebbles, boulder, sand, and mud.
A total of 297 mussels were collected to yield a mean density of 0.598/m2 (Table
2). Eighteen species were collected alive with three species showing signs of recent
recruitment (Villosa vanuxemensis, Medionidus conradicus, Epioblasma brevidens,
length < 30 mm; 1.0% of individuals collected). Two mussel aggregations appeared to
lie parallel to stream flow the larger near the left descending bank and the smaller near
the right descending bank (Figure 9). The most abundant species were Actinonaias
ligamentina (114), Actinonaias pectorosa (56) and Cyclonaias tuberculata (19).
Density of Io fluvialis was 1.02 snails/m2 equaling 506 collected individuals.
Spiny riversnail distribution showed that their highest density was found from markers 0-
100 m along the right descending side of the stream (Figure 10).
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Quantitative
During the Clinchport survey, two quantitative samples were taken. For reporting
purposes, they will be referred to as the right ascending and left ascending sample
because the two sites are linear on either side of the stream channel (Figure 11).
Right ascending sample
The grid for the right ascending quantitative sample was 80 m by 15 m and was
located from transects 60-140 in lanes 40-55. Average depth in this quantitative sample
area was 32.4 cm. In 120-0.25-m2 quadrats, 64 mussels were collected for a density of
0.55/0.25 m2 (Table 3) with a precision of 21.0%. Recent recruitment was seen in three
species, Epioblasma brevidens, Medionidus conradicus and P. fasciolaris (6.25% of
individuals collected). Of the mussels collected, 41% (26) were visible at the surface,
59% (38) were collected subsurface. Individuals of the most common species (A.
ligamentina; 16 collected) were significantly larger on the surface compared to
subsurface collections (P=0.001). A length frequency analysis of both Actinonaias
species (A. ligamentina and A. pectorosa) showed equal lengths from 50 mm to 90 mm
with several large individuals and few small individuals (Figure 12a).
Left ascending sample
The grid for the left ascending quantitative sample was 40 m by 15 m and was
located from transects 100-140 in lanes 5-20. Average depth in this quantitative sample
area was 50.4 cm. In 100-0.25-m2 quadrats, 50 mussels were collected for a density of
0.50/0.25 m2 (Table 4) with a precision of 24.6%. Recent recruitment was seen in one
species, E. brevidens (2.0% of individuals collected). Of the mussels collected, 62% (31)
were visible at the surface, 38% (19) were collected subsurface. The most common
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species (A. ligamentina; 15 collected) showed no significant difference in length of
individuals collected surface vs. subsurface (P=0.087). A length frequency analysis of
both Actinonaias species (A. ligamentina and A. pectorosa) showed a distribution of large
old adults with no individuals smaller than 60 cm (Figure 12b).
Qualitative
A 33.5 person-hour visual search was conducted systematically from the
downstream to upstream end of the survey site. This search yielded 23 species live and 7
represented by relic or fresh dead shell only for a total of 30 species (Table 5). This
sampling added eleven species to our species list (6 live and 5 relic only). Dromus
dromas, Elliptio crassidens, Epioblasma triquetra, Fusconaia cor, Fusconaia cuneolus,
and Ligumia recta were all found live during the qualitative sample but had not been
collected during the earlier quadrat samples.
Incidental
This site is frequently sampled qualitatively to collect broodstock for propagation.
During recent qualitative samples and preliminary site preparation, a live Hemistena lata
and Cyprogenia stegaria were found along with more than one young Quadrula c.
strigillata. These species were not represented in the structured sampling but should
currently be considered extant.
Clinchport 2001 Overview
No report has been compiled for data collected by VDGIF at Clinchport in 2001.
To avoid a long series of unpublished data citations the data from 2001 will be
summarized here and mentioned below in the discussion.
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2001 Semi-quantitative
A total of 799-1-m2 quadrats were sampled yielding 510 mussels and a density of
0.64/m2. Twenty-three species were collected live during semi-quantitative sampling.
2001 Quantitative
Three separate quantitative samples were taken. The first sample included 60-
0.25-m2 quadrats finding 25 mussels for a density of 0.42/0.25 m2. The second sample
included 46-0.25-m2 quadrats finding 66 mussels for a density of 1.43/0.25 m2. It is
believed that the second quantitative sample was taken at the same general area as the
right ascending quantitative sample in the present study. The third and final sample
included 40-0.25-m2 quadrats finding 20 mussels for a density of 0.50/0.25 m2. A grand
total of 146-0.25-m2 quadrats were sampled collecting 19 species live during quantitative
sampling in 2001.
2001 Qualitative
A single 30 minute timed search totaling 5.5 person-hours was conducted, finding
17 live species and 3 represented by relic shell only (Epioblasma f. gubernaculums,
Potamilus alatus and Truncilla truncata).
Discussion
Previous surveys have recorded 36 species live while the current study found 27
with 5 represented by relic shell only. Of previously known species from this location
Alasmidonta marginata, Epioblasma torulosa gubernaculum, Pleurobema coccineum,
Pleurobema cordatum, Pleurobema oviforme, Quadrula intermedia, and Villosa
perpurpurea were not recorded in the present study. The present study collected Dromus
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dromas live and Lemiox rimosus as relic shell only, neither of which had previously been
recorded at the site.
Results of the present study do not show a drastic decline in the mussel
assemblage since 2001. Overall mussel density has only dropped from 0.64/m2 to
0.598/m2. These numbers are not directly comparable as the number of quadrats sampled
varied significantly (799 versus 498); however, the overall density appears to be
relatively stable over the time between samples.
In comparison with a nearby site, Speers Ferry (Clinch RM 211.1), densities are
lower at Clinchport but general abundance stability appears the same. Semi-quantitative
data from the present study (0.55/0.25m2 and 0.50/0.25m2) translates to a density of
2.20/m2 and 2.0/m2. Over 25 years of sampling (1979 to 2004), density at Speers Ferry
has remained stable actually increasing from 3.70/m2 to 4.70/m2 (Ahlstedt et. al 2005).
The first and third 2001 quantitative sample were very consistent with data from
the present study. However, the second quantitative sample was much higher, and it was
believed to be collected at the same location as the 2006 right ascending sample. If these
two quantitative samples overlapped, it shows a striking decline in density (1.43/0.25 m2
down to 0.55/0.25 m2) over the last five years.
The greatest difference between the two data sets is the number of mussel species
collected by sampling type. In 2001, 23 live species were collected in 799-1-m2 quadrats
while the 2006 survey collected only 18 live in 498-1-m2 quadrats. Quantitative (0.25-m2
quadrats) sampling collected 19 species in 2001 in 146-0.25-m2 quadrats while 14 were
collected in 2006 in 220-0.25-m2 quadrats. The largest disparity is between qualitative
sampling data, 19 total species collected in 2001 and 30 collected in 2006.
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These observed differences follow a logical path. More species were found in a
larger effort of one meter quadrats in 2001, while a much greater qualitative sample
collected far more species in 2006. The comparison that may most accurately reflect the
trend in the population is the result of the semi-quantitative sampling. As rare species
decreases in abundance the chance of collecting it in a quadrat decreases as well. The
following species were collected in semi-quantitative sampling in 2001 and then were not
collected in 2006 in the same manner: E. capsaeformis, E. crassidens, F. cor, L. costata,
and Q. c. strigillata each being uncommon in the upper Tennessee River Basin. Two of
these species (L. costata and Q. c. strigillata) were not collected live during any portion
of the structured survey. It is worth mentioning again that the 2006 sample included 74
more 0.25-m2 quadrats, greatly increasing the chance of finding rare species when
compared to the 2001 survey. This evidence points to these rare species currently being
in decline.
Not all results of the present study are negative. Only Ortmanns’ 1913 collection
(1918) recorded more live species than the present study (Table 1). Several species were
collected in sub-adult size ranges (Figure 13), including E. triquetra, which hasn’t been
recorded at Clinchport since Ortmann (1918). Another positive sign is the fact that E.
brevidens was the second most common species collected in the right ascending
quantitative sample.
While recovering sub-adult mussels shows that conditions at the site remain
adequate for juvenile recruitment, a discussion must follow about anthropogenic
disturbances at the study site. The present study site is immediately below the confluence
of the Clinch River at Stock Creek. The Stock Creek watershed contains mining activity
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and other human use impacts which adversely affects its’ water quality. While it may not
be the source of these problems, fewer juvenile mussels and a lower overall density were
recorded on the left ascending side of the river nearest the Stock Creek confluence.
Another recent anthropogenic impact is human activity along the right ascending
side of the river. All terrain vehicles (ATV) have been observed driving along gravel
bars and in the stream channel during periods of low flow. Prior to the present study
large grooves, believed to be ATV tracks, could be seen in the substrate at the site. Shell
fragments of multiple species of various size classes were also observed (Figure 14).
Considering all the various impacts to this site the mussel fauna still persists at a
level near what it was in 2001. Several species can be collected at this site for
propagation including A. ligamentina, A. pectorosa, E. brevidens, E. capsaeformis, L.
fasciola, L. ovata, P. fasciolaris, P. subtentum, and V. iris. As a result of the recently
observed disturbances, and in our opinion low probability of improvement or observing
success at this site, we recommend that restoration activities at this site cease until further
notice. This site may be suitable for restoration activities from a habitat stand point, but
with additional anthropogenic stressors the chance of success is currently deemed too low
to continue stocking of captive reared juveniles.
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Acknowledgements
We wish to thank the following individuals, this survey would not have been
possible without their assistance: Steve Ahlstedt, John Alderman, Braven Beaty, Bill
Bennett, Dave Bova, Bob Butler, Marci Caplis, Pete Constanzer, Hua Dan, Tom
Dickenson, Betty Edmonson, Davis Edmonson, Brian Evans, Shane Hanlon, Mark
Hartman, Roberta Hylton, Justin Laughlin, Jon Lawson, Karen Lynch, Rachel Mair,
Jason Mays, Neil Medlin, Marvin Moriarty, Joey Mullins, Jonathan Orr, Matt Patterson,
Kalena Porter, Brian Roosa, John Schmerfeld, Jonathan Schmerfeld, Chris Sheats, Jen
Smith, Julie Still, Melanie Stine, Craig Walker, Angie Wattland, Juanita Wells, Logan
William, and Amanda Wood.
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Literature Cited Ahlstedt, S. A., M. T. Fagg, R. S. Butler, and J. F. Connell. 2005. Long-term trend
information for freshwater mussel populations at twelve fixed-station monitoring sites in the Clinch and Powell rivers of Eastern Tennessee and Southwestern Virginia (1979-2004). Final Report: U. S. Fish and Wildlife Service, Cookeville, Tennessee. 38p.
Dunn, H.L. 2000. Development of strategies for sampling freshwater mussels (Bivalvia:
Unionidae). Pages 161-167. In Tankersley, R.A., D.I. Warmolts, G.T. Watters, B.J. Armitage, P.D. Johnson, and R.S. Butler (editors). 2000. Freshwater Mollusk Symposia Proceedings. Ohio Biological Survey, Columbus, Ohio. xxi + 274p.
Eckert, N. L., J. J. Ferraro, M. J. Pinder, and B. T. Watson. 2007. Freshwater Mussel and
Spiny Riversnail Survey of SR 833 Bridge and Fletcher Ford, Powell River, Virginia: Augmentation Monitoring Sites – 2004. Final Report: Virginia Department of Game and Inland Fisheries, Richmond. 43p.
Eckert, N. L., J. J. Ferraro, M. J. Pinder, and B. T. Watson. 2008. Freshwater Mussel and
Spiny Riversnail Survey of Slant, Clinch River, Virginia: Augmentation Monitoring Site – 2005. Final Report: Virginia Department of Game and Inland Fisheries, Richmond. 36p.
Neves, R.J. 1999. Conservation and commerce: Management of freshwater mussel
(Bivalvia: Unionoidea) resources in the United States. Malacologia 40(1-2):461-474.
Strayer, D.L., and D.R. Smith. 2003. A Guide to Sampling Freshwater Mussel
Populations. American Fisheries Society, Monograph 8, Bethesda, Maryland.
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Table 1. Previous mussel collections in the Clinch River at or near Clinchport.
Species 18991 19131 19792 19882 19942 19992 20013 20042 Present Study4
A. ligamentina L L L L L L L L LA. pectorosa L L L L L L L L LA. marginata L L A. plicata L L L L LC. tuberculata L L L L L LC. stegaria L L L LD. dromas LE. crassidens L L L LE. dilatata L L L L L L L LE. brevidens L L L L L L LE. capsaeformis L L L L L LE. t. gubernaculum L L E. triquetra L LF. barnesiana L L RF. cor L L L L LF. cuneolus L L L LF. subrotunda L L L L L LH. lata L LL. fasciola L L L L L L LL. ovata L L L L LL. costata L L L L L L RL. rimosus RL. dolabelloides L LL. recta L L LM. conradicus L L L L L L L LP. cyphyus L L LP. coccineum L P. cordatum L P. oviforme L P. alatus L L R RP. fasciolaris L L L L L L LP. subtentum L L L L L L LQ. c. strigillata L L L LQ. intermedia L Q. pustulosa L LT. truncata R RV. iris L L L LV. perpurpurea L L V. vanuxemensis L L
Live 20 29 11 13 10 9 24 10 27Relic -- -- -- -- -- -- 2 -- 5Total 20 29 11 13 10 9 26 10 321Records from Ortmann (1918) 2 Records courtesy of Steve Ahlstedt, USGS, Collection site Speers Ferry, CRM 211.1 3 Previous DGIF mussel augmentation site survey at Clinchport June 5th-7th, 2001. 4 Present study conducted at Clinchport from August 15th-17th, 2006.
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Table 2. Total number and density of mussel species collected during semi-quantitative sampling of the Clinch River at Clinchport. Individuals measuring less than 30 mm were considered juveniles.
Species Total Collected
Number of Juveniles
Percent of Collection
Density (per m2)
Actinonaias ligamentina 114 0 38.4 0.229 Actinonaias pectorosa 56 0 18.9 0.112 Cyclonaias tuberculata 19 0 6.4 0.038 Ptychobranchus fasciolaris 18 0 6.1 0.036 Lampsilis fasciola 16 0 5.4 0.032 Amblema plicata 15 0 5.0 0.031 Epioblasma brevidens 15 1 5.0 0.031 Medionidus conradicus 15 1 5.0 0.031 Villosa iris 6 0 2.0 0.012 Elliptio dilatata 3 0 1.0 0.006 Epioblasma capsaeformis 3 0 1.0 0.006 Lampsilis ovata 3 0 1.0 0.006 Plethobasus cyphyus 3 0 1.0 0.006 Ptychobranchus subtentum 3 0 1.0 0.006 Villosa vanuxemensis 3 1 1.0 0.006 Fusconaia subrotunda 2 0 0.7 0.004 Quadrula pustulosa 2 0 0.7 0.004 Lexingtonia dolabelloides 1 0 0.4 0.002 Cyprogenia stegaria 0 0 0 0 Dromus dromas 0 0 0 0 Elliptio crassidens 0 0 0 0 Epioblasma triquetra 0 0 0 0 Fusconaia barnesiana 0 0 0 0 Fusconaia cor 0 0 0 0 Fusconaia cuneolus 0 0 0 0 Lasmigona costata 0 0 0 0 Lemiox rimosus 0 0 0 0 Ligumia recta 0 0 0 0 Pleurobema oviforme 0 0 0 0 Potamilus alatus 0 0 0 0 Quadrula c. strigillata 0 0 0 0
Total 297 3 100 0.598
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Table 3. Total number and density of mussel species collected in the Clinch River at Clinchport in the right ascending quantitative sample. Individuals measuring less than 30 mm were considered juveniles.
Species Total Collected
Number of Juveniles
Percent of Collection
Density (per 0.25m2)
Actinonaias ligamentina 16 0 25.0 0.133 Epioblasma brevidens 13 2 20.3 0.108 Ptychobranchus fasciolaris 9 1 14.0 0.075 Actinonaias pectorosa 7 0 10.9 0.059 Medionidus conradicus 6 1 9.4 0.051 Cyclonaias tuberculata 4 0 6.2 0.033 Ptychobranchus subtentum 4 0 6.2 0.033 Elliptio dilatata 1 0 1.6 0.008 Fusconaia subrotunda 1 0 1.6 0.008 Lampsilis fasciola 1 0 1.6 0.008 Lampsilis ovata 1 0 1.6 0.008 Villosa iris 1 0 1.6 0.008 Amblema plicata 0 0 0 0 Cyprogenia stegaria 0 0 0 0 Dromus dromas 0 0 0 0 Elliptio crassidens 0 0 0 0 Epioblasma capsaeformis 0 0 0 0 Epioblasma triquetra 0 0 0 0 Fusconaia barnesiana 0 0 0 0 Fusconaia cor 0 0 0 0 Fusconaia cuneolus 0 0 0 0 Lasmigona costata 0 0 0 0 Lemiox rimosus 0 0 0 0 Lexingtonia dolabelloides 0 0 0 0 Ligumia recta 0 0 0 0 Plethobasus cyphyus 0 0 0 0 Pleurobema oviforme 0 0 0 0 Potamilus alatus 0 0 0 0 Villosa vanuxemensis 0 0 0 0 Quadrula c. strigillata 0 0 0 0 Quadrula pustulosa 0 0 0 0
Total 64 4 100 0.55
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Table 4. Total number and density of mussel species collected in the Clinch River at Clinchport in the left ascending quantitative sample. Individuals measuring less than 30 mm were considered juveniles.
Species Total Collected
Number of Juveniles
Percent of Collection
Density (per 0.25m2)
Actinonaias ligamentina 15 0 30.0 0.15 Actinonaias pectorosa 9 0 18.0 0.09 Lampsilis fasciola 6 0 12.0 0.06 Epioblasma brevidens 4 1 8.0 0.04 Ptychobranchus fasciolaris 4 0 8.0 0.04 Cyclonaias tuberculata 2 0 4.0 0.02 Elliptio dilatata 2 0 4.0 0.02 Lampsilis ovata 2 0 4.0 0.02 Medionidus conradicus 2 0 4.0 0.02 Ptychobranchus subtentum 2 0 4.0 0.02 Amblema plicata 1 0 2.0 0.01 Plethobasus cyphyus 1 0 2.0 0.01 Cyprogenia stegaria 0 0 0 0 Dromus dromas 0 0 0 0 Elliptio crassidens 0 0 0 0 Epioblasma capsaeformis 0 0 0 0 Epioblasma triquetra 0 0 0 0 Fusconaia barnesiana 0 0 0 0 Fusconaia cor 0 0 0 0 Fusconaia cuneolus 0 0 0 0 Fusconaia subrotunda 0 0 0 0 Lasmigona costata 0 0 0 0 Lemiox rimosus 0 0 0 0 Lexingtonia dolabelloides 0 0 0 0 Ligumia recta 0 0 0 0 Pleurobema oviforme 0 0 0 0 Potamilus alatus 0 0 0 0 Quadrula c. strigillata 0 0 0 0 Quadrula pustulosa 0 0 0 0 Villosa iris 0 0 0 0 Villosa vanuxemensis 0 0 0 0
Total 50 1 100 0.5
22
Table 5. Live and relic mussel species collected in the Clinch River at Clinchport during qualitative sampling, August 2006.
Species 0 20 40 60 80 100 120 140 160 Present Overall
Actinonaias ligamentina L L L L L L L L L L Actinonaias pectorosa L L L L L L L L L L Amblema plicata L L L L L L L L L L Cyclonaias tuberculata L L L L L L L L L L Cyprogenia stegaria Dromus dromas L L Elliptio dilatata R R L L L L R R L Elliptio crassidens R R R L R L Epioblasma brevidens R L L L L L L L R L Epioblasma capsaeformis R L R L R L Epioblasma triquetra L R L Fusconaia barnesiana R R Fusconaia cor L R R R R R L Fusconaia cuneolus L R L Fusconaia subrotunda R L R L L L R R L L Hemistena lata Lampsilis fasciola R R L R R L L L L L Lampsilis ovata R L L R L L L Lasmigona costata R R R R R Lemiox rimosus R R Lexingtonia dolabelloides L L Ligumia recta R R R R R R R L L Medionidus conradicus L L L L L L L L L L Plethobasus cyphyus R L L L L L L L Pleurobema oviforme Potamilus alatus R R R R R R R Ptychobranchus fasciolaris L L L L L L L L L Ptychobranchus subtentum R L L R R R L L Quadrula c. strigillata R R R Quadrula pustulosa R R R R R L L Truncilla truncata R R Villosa iris R R R L L L L L L Villosa vanuxemensis R R R R R R
Live 6 9 11 14 13 16 14 10 9 23
Relic 10 10 6 6 8 6 8 8 8 7
Total 16 19 17 20 21 22 22 18 17 30
23
Table 6. Mussel species collected in the Clinch River at Clinchport based on type of sampling employed. Qualitative reflect all species collected live, fresh dead or relic; other samples are live collections only.
Species Semi-Quantitative Quantitative Qualitative Incidental* Overall
Actinonaias ligamentina X X X X Actinonaias pectorosa X X X X Amblema plicata X X X X Cyclonaias tuberculata X X X X Cyprogenia stegaria X X Dromus dromas X X Elliptio dilatata X X X X Elliptio crassidens X X Epioblasma brevidens X X X X Epioblasma capsaeformis X X X Epioblasma triquetra X X Fusconaia barnesiana X X Fusconaia cor X X Fusconaia cuneolus X X Fusconaia subrotunda X X X X Hemistena lata X X Lampsilis fasciola X X X X Lampsilis ovata X X X X Lasmigona costata X X Lemiox rimosus X X Lexingtonia dolabelloides X X X Ligumia recta X X Medionidus conradicus X X X X Plethobasus cyphyus X X X X Pleurobema oviforme Potamilus alatus X X Ptychobranchus fasciolaris X X X X Ptychobranchus subtentum X X X X Quadrula c. strigillata X X X Quadrula pustulosa X X X Truncilla truncate X X Villosa iris X X X X Villosa vanuxemensis X X X
Totals 18 14 30 3 32 * Incidental records are reserved for rare and endangered species that were found live coincidentally.
24
Figure 1. Stream reaches designated as augmentation reaches by the Virginia Department of Game and Inland Fisheries mussel restoration plan. Six reaches are divided between the Powell River (1), Clinch River (4) and North Fork Holston River (1).
25
Figure 2. Location of present study with relation to the town of Clinchport, Stock Creek, and a DGIF boat ramp in Scott County, Virginia.
26
Figure 3. Elevated view of the Clinch River at Clinchport, Scott County, Virginia. Site of the present study in 2006. Ropes with flagging provide a visual guide for samplers moving upstream.
27
Figure 4. Overhead view of a survey site. Ropes are stretched every 40 meters with flags every 5 meters to delineate lanes and serve as a visual guide. Black lines show one lane.
40M
28
44m
Figure 5. Representation of semi-quantitative sampling method at a site 44m wide. Squares indicate sampling location and lines show lane boundaries. Each lane is 5m wide and 20m long. Five samples are taken representing 5% of overall habitat. Starting position of samplers alternates between 1m and 3m.
20m
5m
22m 27m 17m 32m 37m 42m 12m 7m 2m
29
Figure 6. The Ferraro streambed sampler. This sampler is made with perforated aluminum and was designed to hold all substrate excavated from a 0.25 m2 quadrat.
30
Figure 7. Location of 1m quadrats sampled during semi-quantitative sampling at Clinchport.
31
Figure 8. Depth profile of the Clinch River at Clinchport, August 2006. Stream discharge approximately 300 cubic feet per second.
32
Figure 9. Relative abundance and location of mussels collected at Clinchport during the present study.
33
Figure 10. Relative abundance and location of spiny riversnail, Io fluvialis, collected during the present study.
34
Figure 11. Clinchport mussel abundance and location. Box indicates sites selected for quantitative sampling.
35
A Length distribution of Actinonaias in Right Ascending
Quantitative Sample
0
1
2
3
4
5
6
10 20 30 40 50 60 70 80 90 100 110 120
Lenght (mm)
Num
ber C
olle
cted
SubsurfaceSurface
B Length Distribution of Actinonaias collected in Left Ascending
Quantitative Sample
0
1
2
3
4
5
6
7
10 20 30 40 50 60 70 80 90 100 110 120
Length (mm)
Num
ber C
olle
cted
SurfaceSubsurface
Figure 12. Length frequency diagram of Actinonaias pectorosa and Actinonaias ligamentina collected during two quantitative samples of the Clinch River at Clinchport, 2006. Right ascending sample (A) taken from right ascending portion of the stream, while left ascending sample (B) was taken from left ascending side.
36
Figure 13. Sub-adult specimen collected during qualitative sampling at Clinchport, 2006. Starting clockwise from top left species include: P. fasciolaris, L. fasciola, L. ovata, E. triquetra, E. brevidens, E. capsaeformis, M. conradicus, and V. iris (center).
37
Figure 14. Shell fragment collected in the Clinch River at Clinchport during 2006. It is believed that mussel was crushed by ATV traffic that was evident in the streambed during low flow conditions of 2006. The shell is a federally endangered E. brevidens female.
38
39
Appendix 1. Scientific name, common name, Virginia wildlife action plan tier, state and federal status of species mentioned in this report.
Species Name Common Name WAP Tier State* Federal*
Actinonaias ligamentina mucket --- ----- ----- Actinonaias pectorosa pheasantshell --- ----- ----- Alasmidonta marginata elktoe III SSC SOC Amblema plicata threeridge --- ----- ----- Cyclonaias tuberculata purple wartyback --- ----- ----- Cyprogenia stegaria fanshell I SE FE Dromus dromas dromedary pearlymussel I SE FE Elliptio crassidens elephantear IV SE ----- Elliptio dilatata spike --- ----- ----- Epioblasma brevidens Cumberland combshell I SE FE Epioblasma capsaeformis oystermussel I SE FE Epioblasma t. gubernaculum green blossom I SE FE Epioblasma triquetra snuffbox II SE SOC Fusconaia barnesiana Tennessee pigtoe II SSC ----- Fusconaia cor shiny pigtoe I SE FE Fusconaia cuneolus finerayed pigtoe I SE FE Fusconaia subrotunda longsolid III ----- SOC Hemistena lata crackling pearlymussel I SE FE Io fluvialis spiny riversnail III ST SOC Lampsilis cardium plain pocketbook --- ----- ----- Lampsilis fasciola wavyrayed lampmussel --- ----- ----- Lampsilis ovata pocketbook IV ----- ----- Lemiox rimosus birdwing pearlymussel I SE FE Lexingtonia dolabelloides slabside pearlymussel II ST FC Ligumia recta black sandshell III ST ----- Medionidus conradicus moccasinshell --- ----- ----- Plethobasus cyphyus sheepnose II ST FC Pleurobema coccineum round pigtoe --- ----- ----- Pleurobema cordatum Ohio pigtoe III SOC SE Pleurobema oviforme Tennessee clubshell III ----- SOC Potamilus alatus Pink heelsplitter --- ----- ----- Ptychobranchus fasciolaris kidneyshell --- ----- ----- Ptychobranchus subtentum fluted kidneyshell II ----- FC Quadrula c. strigillata rough rabbitsfoot I SE FE Quadrula pustulosa pimpleback IV ST ----- Truncilla truncata deertoe IV SE ----- Villosa iris rainbow --- ----- ----- Villosa vanuxemensis mountain creekshell IV ----- ----- * FE=Federally Endangered, SOC=Federal Species of Concern, FC=Federal Candidate, SE=State Endangered, ST=State Threatened, SSC=State Species of Concern.